EN
Let a,b,c be fixed coprime positive integers with min{a,b,c} > 1, and let m = max{a,b,c}. Using the Gel'fond-Baker method, we prove that all positive integer solutions (x,y,z) of the equation $a^x+b^y = c^z$ satisfy max{x,y,z} < 155000(log m)³. Moreover, using that result, we prove that if a,b,c satisfy certain divisibility conditions and m is large enough, then the equation has at most one solution (x,y,z) with min{x,y,z} > 1.